Search

The depletion of fossil fuels and onset of global warming dictate the achievement of efficient technologies for clean and renewable energy sources. The conversion of solar energy into chemical energy plays a vital role both in energy production and environmental protection. A photocatalytic approach for H2 production and CO2 reduction has been identified as a promising alternative for clean energy production and CO2 conversion. In this process, the most critical parameter that controls efficiency is the development of a photocatalyst. Two-dimensional nanomaterials have gained considerable attention due to the unique properties that arise from their morphology. In this paper, examples on the development of different 2D structures as photocatalysts in H2 production and CO2 reduction are discussed and a perspective on the challenges and required improvements is given.

Αντικείμενο της διατριβής αποτελεί η μελέτη των γυναικείων ενδεδυμένων και ημιενδεδυμένων μορφών ελληνιστικών χρόνων από τα νησιά των Κυκλάδων. Στόχος της εργασίας είναι η εξέταση των μορφών σε συνάρτηση κατά κύριο λόγο με την εποχή κατά την οποία λαξεύτηκαν, συμβάλλοντας στην μελέτη της ελλιπώς ακόμη γνωστής τέχνης της ελληνιστικής περιόδου από τις Κυκλάδες. Η διατριβή διαρθρώνεται σε ένα μέρος κειμένου (Μέρος Ι) και ένα μέρος καταλόγου και εικόνων (Μέρος ΙΙ). Στα εισαγωγικά κεφάλαια αναπτύσσονται οι στόχοι και η μεθοδολογία της μελέτης, η ιστορία της έρευνας και δίνεται μία επισκόπηση της ιστορίας των νησιών. Το εκτενέστερο τμήμα αποτελεί η παρουσίαση των νησιών και η συζήτηση για τους ακολουθούμενους αγαλματικούς τύπους. Οι μορφές, μικρά, μεσαίου και μεγαλύτερου μεγέθους ολόγλυφα έργα θνητών και θεοτήτων, χρονολογήθηκαν με βάση κυρίως την τεχνοτροπία τους σε ευρείες χρονολογικές ενότητες. Παράλληλα αναζητήθηκε ο χαρακτήρας των γλυπτών (λατρευτικός, αναθηματικός, τιμητικός, επιτύμβιος) και η ένταξή τους στην κοινωνικοπολιτική ιστορία και τοπογραφία των νησιών. Για την πληρότητα της έρευνας παρουσιάθηκε η σχέση του εργαστηρίου της Δήλου με τις υπόλοιπες Κυκλάδες και το επιγραφικό υλικό ελληνιστικών χρόνων που αφορά στη θέση των γυναικών στα νησιά. Κατακλείδα της διατριβής αποτελεί η ενότητα των γενικών συμπερασμάτων. Το υλικό που χρησιμοποιήθηκε είναι στις περισσότερες περιπτώσεις καλής ποιότητας λευκό μάρμαρο, λεπτόκοκκο ή χονδρόκοκκο. Συχνή είναι η χρήση του παριανού ή πεντελικού μαρμάρου. Τα περισσότερα γλυπτά είναι μικρότερα του φυσικού μεγέθους και δη αγαλμάτια. Τα μικρά έργα είχαν αναλογικά και χαμηλότερο κόστος, μεταφέρονταν εύκολα και τοποθετούνταν παντού. Τα περισσότερα έργα είναι μάλλον διακοσμητικά, προορισμένα να κοσμήσουν εσωτερικούς ή εξωτερικούς χώρους, δημόσιους και ιδιωτικούς και αναθηματικά. Λίγα έργα, σε κλίμακα μεγαλύτερη του φυσικού, είχαν λατρευτική χρήση. Στην πλειονότητά τους εικονίζουν θεότητες, με την Αφροδίτη και την Αρτέμιδα να έχουν την μεγαλύτερη αντιπροσώπευση. Ωστόσο δεν λείπουν τα έργα που εικονίζουν θνητές, ιέρειες ή απλές ευκατάστατες αστές. Οι δημοφιλέστεροι αγαλματικοί τύποι είναι εκείνοι της «Μεγάλης Ηρακλειώτισσας» και της Pudicitia. Στην πλειόνοτητά τους τα έργα που εξετάστηκαν, χρονολογούνται στους ύστερους ελληνιστικούς χρόνους, την αρχή δηλαδή της ρωμαιοκρατίας για τα νησιά των Κυκλάδων. Το γεγονός αυτό θα πρέπει να σχετίζεται με την ευμάρεια που απολαμβάνουν οι ευκατάστατοι πολίτες των νησιών αλλά και με τη δράση των Ιταλών πραγματευομένων. Ως προς τους γενικούς αγαλματικούς τύπους αντανακλώνται λιγότερο ή περισσότερο πιστά κλασικά και υστεροκλασικά πρότυπα ή αντιγράφονται ελληνιστικές δημιουργίες με επιμέρους μοτίβα, που ενσωματώνονται στο σύγχρονό τους καλλιτεχνικό πλαίσιο. Η τεχνοτροπική ανάλυση κατέδειξε την πολλαπλότητα των τεχνοτροπικών στοιχείων ως απόρροια του κοσμοπολίτικου χαρακτήρα των νησιών. Kάποιες από τις μορφές θα μπορούσαν να θεωρηθούν ενδεικτικές της λειτουργίας τοπικών εργαστηρίων, τουλάχιστον για την εξυπηρέτηση των τοπικών καθημερινών αναγκών. Οι Κυκλάδες αποτέλεσαν ζωτικό καλλιτεχνικό κέντρο, που δεν περιορίσθηκε μόνο σε επαναλήψεις θεμάτων και μοτίβων άλλων σχολών, αλλά δημιουργούσε και επανεπεξεργαζόταν τα στοιχεία που υιοθετούσε κάθε φορά.

Metal–organic frameworks are recognized as a new generation of emerging porous materials in a variety of applications including adsorption and photocatalysis. The present study presents the development of ternary composite materials made through the coupling of UiO-66 with palygorskite (Pal) clay mineral and titanium dioxide (TiO2) applied as adsorbent and photocatalyst for the removal of methyl orange (MO) from aqueous solutions as a typical anionic dye. The prepared materials were characterized using XRD, ATR, DR UV/Vis, and TGA analysis. Detailed kinetic experiments revealed that the presence of the clay at low amounts in the composite outperformed the adsorption efficiency of pure UiO-66, increasing MO adsorption by ca. 8%. In addition, coupling Pal/UiO-66 with TiO2 for the production of ternary composites provided photocatalytic properties that resulted in complete removal of MO. This was not observed in the pure UiO-66, the Pal/UiO-66 composite, or the pure TiO2 material. This study presents the first example of clay mineral/MOF/TiO2 composites with improved performance in removing dyes from aqueous solutions and highlights the importance of coupling MOFs with low-cost clay minerals and photocatalysts for the development of multifunctional advanced composites.

Herein, a novel composite material containing UiO-66 and palygorskite (Pal) clay mineral was prepared using a facile one-pot synthesis process. The material was studied using a variety of techniques and applied as did not affect the structure of the metal-organic framework (MOF) part, but induced a small increase in specific surface area. The developed Pal/UiO-66 composite presented excellent adsorption efficiency against MO removal, as evidenced by detailed kinetic and isotherm experiments. An impressive maximum adsorption capacity at equilibrium was evidenced; 340 mg g−1 at pH = 5 and T = 25 °C. This corresponds to a 34.5 % increase compared with pure UiO-66, considering only the MOF content. Furthermore, the Pal/UiO-66 composite was proven stable and highly recyclable, losing less than 9% of the removal capacity after five consecutive cycles. The study highlights the synergistic effect of the coupling of MOF structures with low-cost and abundant clay minerals for the development of advanced absorbents.

This paper explores the adoption of Paul Samuelson’s Public Good Theory as a theoretical justification for a permissive licensing scheme enabling the use, and re-use orphan works in Malaysia. Orphan works are copyright-protected works with unlocatable or unidentified right holders, and are currently on the rise due to the proliferation of unregistered, anonymous, and abandoned copyright works. The literature denotes the challenges arising from the difficulty faced by potential users in obtaining the permission for creative and innovative use of orphan works as required under Copyright law. Such challenges impede the potential use and re-use of orphan works for the purpose of knowledge dissemination, progress in the arts, preservation and digitisation activities. This paper contributes to the current body of knowledge by canvassing two important issues. The first issue focuses on the challenges faced by potential users to use and re-use orphan works in Malaysia. The second is Paul Samuelson’s Public Good as a theoretical justification for permissive license to use and re-use orphan works. It is anticipated that a legislative reform grounded on Paul Samuelson’s Public Good Theory will spur grassroots innovations, creativity and entrepreneurialism among members of the public. The permissive licensing scheme supports global calls for legislative reform of copyright law to facilitate the use and reuse of orphan works.

Background Postanesthesia emergence delirium is a motor agitation state complicating pediatric anesthesia. We investigated the efficacy of dexmedetomidine in reducing emergence delirium in children undergoing tonsillectomy with and without adenoidectomy using total intravenous anesthesia with propofol. Methods This was a prospective, single-center, double-blind, randomized study. The primary outcome was the presence or absence of emergence delirium with and without dexmedetomidine. Secondary outcomes were emergence delirium severity, time to extubation, cardiovascular stability, and need for additional postoperative analgesia. Eligible were children 3-14 years of age, ASA I or II, scheduled for tonsillectomy with or without adenoidectomy. Patients were randomized to receive dexmedetomidine 1 mcg kg-1 or a volume matched normal saline solution. Presence of emergence delirium and agitation severity was assessed with the Watcha scale 10, 20, and 30 minutes after arrival in the postanesthesia care unit. Results Sixty children participated to the study, 31 (51.7%) of them were treated with dexmedetomidine. Their mean age was 6.2 years (SD 5.5). Duration of anesthesia and surgery and blood pressure measurements did not differ between groups. Extubation time was not different between groups. The dexmedetomidine group had a significantly lower frequency of emergence delirium compared with no dexmedetomidine after 20 and 30 minutes in postanesthesia care unit: 16.1% and 12.9% at 20 and 30 minutes in the dexmedetomidine group vs 48.3% and 41.4% in in the no dexmedetomidine group. Conclusion Dexmedetomidine 1 mcg kg-1 reduces the incidence and severity of emergence delirium after tonsillectomy with propofol anesthesia without prolonging the extubation time.

We present and evaluate a procedure that utilizes mobility and throughput prediction to prefetch video streaming data in integrated cellular and WiFi networks. The effective integration of such heterogeneous wireless technologies will be significant for supporting high performance and energy efficient video streaming in ubiquitous networking environments. Our evaluation is based on trace-driven simulation considering empirical measurements and shows how various system parameters influence the performance, in terms of the number of paused video frames and the energy consumption. The proposed approach has been implemented in an Android-based prototype.

We present a detailed evaluation of procedures that exploit mobility prediction and prefetching to enhance offloading of traffic from mobile networks to WiFi hotspots, for both delay tolerant and delay sensitive traffic. We consider empirical measurements and evaluate the percentage of offloaded traffic, data transfer delay, and energy consumption of the proposed procedures. Our results illustrate how various factors such as mobile, WiFi and hotspot backhaul throughput, data size, number of hotspots, along with time and throughput estimation errors, influence the performance and energy efficiency of mobile data offloading enhanced with mobility prediction and prefetching., Comment: Proc. IEEE Workshop on Convergence among Heterogeneous Wireless Systems in Future Internet (CONWIRE), held in conjunction with IEEE WoWMoM, June 2013. arXiv admin note: substantial text overlap with arXiv:1306.3177

A proportion of cases of HC after allo-SCT are associated with infection from BKV. Supportive treatment is not sufficient for the relief of symptoms in many patients with BKV-associated HC. Cidofovir is an antiviral agent active against BKV. Its use is limited, however, due to the reported risk of renal failure in patients with cytomegalovirus (CMV) infection. The experience with cidofovir in BKV-associated HC is anecdotal, and the optimal dose schedule of the drug has not been determined. We administered weekly high-dose cidofovir in 5 patients for the treatment of 6 episodes of symptomatic BKV-associated HC, which were refractory to first-line therapy with hydration and continuous bladder irrigation. One patient was treated twice with cidofovir for 2 temporally separated episodes of HC, combined with papillary necrosis and ureteritis respectively. All 5 patients were males, aged 21–44 years, and had received grafts from matched related (n=2), matched unrelated (n=1) or haploidentical (n=1) donors. The median time from transplantation to diagnosis of HC was 61.5 (range, 26–303) days. In all cases, the development of HC was associated with severe immunosuppression due to profound lymphopenia or treatment with steroids or antithymocyte globulin for GVHD. BKV-associated HC was confirmed by detection of BKV in the urine by real-time PCR (1.5 × 107–5.5 × 109 copies/ml). In 2 of the 6 episodes, the patients also developed BKV viremia (5.0–9.9 × 103 copies/ml). The median time from the manifestation of symptoms to initiation of cidofovir was 12 (range, 4–53) days. Cidofovir was started at a dose of 2.5 mg/kg/week intravenously over 1 hour. If renal function remained stable, subsequent doses of 5 mg/kg were given at weekly intervals for a total of 4–6 doses. Oral probenecid and intravenous hydration were administered in combination with cidofovir. No patient developed renal toxicity (a rise in serum creatinine of at least 1.5 × baseline or proteinuria). In 5 of the 6 cases, clinical improvement of patients was observed, with a median time to response of 5 (range, 3–8) days after the first dose of cidofovir. Complete resolution of symptoms of HC was achieved in these 5 cases after 4 to 6 doses of cidofovir. BKV viral load was monitored weekly in urine (and blood) during therapy. Clinical responses did not correlate with a reduction in viral load in urine. However, in the 2 cases with BKV viremia, real-time PCR became negative after treatment with cidofovir. Concomitant CMV infection was detected in 5 of the 6 episodes of BKV-associated HC, and in all but one, complete suppression of CMV reactivation was achieved by cidofovir. Four of the 5 patients are currently alive and free of symptoms of HC. In conclusion, treatment of BKV-associated HC with cidofovir at the dose of 5 mg/kg/week seems to be safe and may result in prompt and sustained relief of the debilitating symptoms of this condition. Additional manifestations of BKV-associated disease (papillary necrosis and ureteritis) and concurrent CMV infection can be managed successfully with this dose schedule. To our knowledge, these 6 cases comprise the largest reported experience of treatment of BKV-associated HC with cidofovir, albeit the encouraging results need to be substantiated by further trials.